The lipid droplet protein Jabba promotes actin remodeling downstream of prostaglandin signaling during Drosophila oogenesis.

Growing evidence supports that lipid droplets (LD) are critical for producing high-quality oocytes. However, the functions of LDs during oocyte development remain largely unknown. Using Drosophila oogenesis as a model, we previously discovered that the LD-associated Adipose Triglyceride Lipase (ATGL) promotes actin remodeling necessary for oocyte development by providing the substrate for producing lipid signals termed prostaglandins (PG). Here, we find that Jabba, a LD-associated protein best known for its role in anchoring other proteins to LDs, also promotes PG-dependent actin remodeling. Overexpression of Jabba results in thickened cortical actin and excessive actin bundles, whereas loss of Jabba results in cortical actin breakdown and severely defective actin bundle formation. We find that Jabba regulates actin remodeling in conjunction with PG signaling. However, the lack of a genetic interaction between Jabba and ATGL suggests the PG-Jabba pathway is independent of ATGL. These data are consistent with the model that there are multiple PG signaling pathways promoting actin remodeling. Overexpression of Jabba rescues the actin defects when PG signaling is lost. Together, these data lead to the model that PGs produced independently of ATGL positively regulate Jabba to promote actin remodeling necessary for follicle morphogenesis.